[Excerpt] This study of 105 dining parties at a casual chain restaurant found that a male server received significantly larger tips when he touched the shoulder of the person paying the bill than when he did not touch the customer. This touch effect on tips was essentially the same whether the touch was for two or four seconds, and whether the customer being touched was male or female. The age of the customer, however, did have a significant effect on the extent to which the touch increased the server's tips. Young customers responded more positively to the touch than did older diners. Nevertheless, the older diners who were touched did increase their tips compared to like-aged diners who weren't touched at all. Restaurant managers' personal objections to promoting touching seem to be misguided in light of these and other experimental data, and their fears of legal repercussions from touching customers are groundless.
Lynn, M. (1998). Reach out and touch your customers [Electronic version]. Cornell Hotel and Restaurant Administration Quarterly, 39(3), 60-65. Retrieved [insert date], from Cornell University, School of Hospitality Administration site: http://scholarship.sha.cornell.edu/articles/112/